password.rb

module Password
  CHARS = [*('A'..'Z'), *('a'..'z'), *(0..9), '$']

  def self.generate(size = 4)
    chunks = []
    size.times do
      chunks << create_chunk
    end
    chunks.join('-')
  end

  def self.create_chunk(size = 4)
    CHARS.sample(size).join
  end
end

puts Password.generate